The Democratic presidential hopeful John Edwards rallied supporters last night with a fiery speech and a performance by rock star John Mellencamp.

With the end of a year of campaigning less than 24 hours away, more than 3,000 people braved the cold night air and packed into the Val Air ballroom outside Des Moines.

The former North Carolina senator's rhetoric chimed well with the melodies of Mellencamp - an Indiana singer who echoes Edwards' populist, everyman tone.

Coming off a 36-hour marathon of non-stop campaigning, Edwards gave a slightly shortened version of his standard stump speech that nevertheless had the audience applauding louder than they did for the rock star.

Edwards stuck to the anti-corporate rhetoric that has earned him rural and union support but opened him to criticism that he's too angry to get things done in Washington.

"Corporate greed is robbing our children of the promise of America and it is time for us to fight back, it is time for us to stand up," he said to cheers. "Tomorrow night, you need to send a fighter and a warrior into that arena on your behalf."

Edwards also unleashed a fresh line of attack on his rivals for the Democratic nomination, senators Hillary Clinton and Barack Obama. "You know the difference between somebody for whom this is academic, philosophical or political, and someone who is speaking from here," he said, pointing to his heart.

"If it is political and academic, when the going gets rough they will walk away."

Mellencamp performed a solo acoustic set, offering renditions of five hit songs that described life in small-town America, like the mill town in which Edwards grew up. At one point, he led the audience in a chorus: "From the east coast, to the west coast, down the Dixie highway, back home. This is our country."

For the most part Mellencamp refrained from overt political speech, although he did indulge in a dig at the Bush administration. "They were going to pay for this war with oil profits, isn't that what they said," he said, to cheers.

Despite the star power, the majority of the audience said they showed up for Edwards rather than the rock concert. Dan Malloy, a Des Moines resident and former military policeman (MP) in Iowa's national guard, said he thought Edwards was the best candidate for veterans, and more sincere than Obama.

"There's one thing about being an MP: you can pretty much tell when someone is straight laced or bullshitting you," he said. "He seems to be honest."

But Tod Miller, a Des Moines IT worker who was torn between the candidates, said Edwards' tone threatened to turn him off. "I like the fresh message, but he also scares me," he said. "I work for corporate America, and I'm here to reconcile my fears with my job."